Throughout the years, people have sought to modify the color of their skin, their eyelashes or their hair. Several techniques have been developed to achieve the desired color.
It is known to dye human keratinous substrates, such as the hair, with dye compositions comprising oxidation dye precursors, which are also known as oxidation bases. To vary the shades obtained with these oxidation bases, additional couplers or coloration modifiers may be employed.
It is also known to dye human keratinous substrates by direct dyeing, which comprises applying to the keratinous substrates direct dyes, which are colored.
Traditional application time for dyeing keratinous substrates is around thirty minutes. Such a period is considered to be too long under current tendency.
This problem cannot be solved by merely reducing the application time of the dyeing compositions since it would be difficult to maintain the same satisfactory levels of coloring in shortened application times.
Another way to solve the problem is to increase the power of the oxidizing agent and the alkaline agent, by employing, for example, oxidizing agents of the type of the persalts, and/or alternatively by increasing the pH of the dyeing composition. However, such an option is undesirable, because of the increased risk of degradation of the keratinous substrates.
Therefore, there is a real need to develop dyeing compositions with improved efficiency to yield minimum degradation of the treated keratinous substrates while achieving improved levels of coloring in both conventional application time e.g., around 30 minutes and in shortened application times, e.g., around 15 minutes.
Another object of the present invention is to provide an effective dyeing composition capable of depositing acceptable levels of color onto keratinous substrates utilizing decreased levels of dye therein.
It is also desirable that such a composition can provide other advantageous properties to the hair such as shine, conditioning and a healthy appearance. Finally, it is an object of the present invention to provide an effective dyeing composition with lowered cost of production.